When Anthony Joshua steps into the ring at the ExCeL Arena on Sunday afternoon, almost certainly for the last time as an amateur before he heads for the United States and all that the professional game has to offer, he will put the final imprint on what has been an extraordinary Olympic boxing tournament, for himself, his team-mates and his country.

The super-heavyweight from Watford, still only 22, has boxed for only four years yet, if he beats the reigning Olympic champion, a Milanese policeman 10 years his senior, Roberto Cammarelle, he will announce himself at the summit of the amateur sport in the most emphatic way.

An Olympic gold medal in the glamour weight classes from middleweight to the showpiece division above 91kg, historically, has been a passport to riches, although some have travelled further than others and a few have lost their way completely.

Muhammad Ali, a winner at light-heavweight in Rome in 1960, became the most famous athlete (person, even) in the world. Audley Harrison made a quick pile after winning at super-heavyweight in Sydney 12 years ago, then fell a good deal short of the ultimate achievement, the world heavyweight title.

For Joshua the landscape has shifted. What was once the biggest prize in sport no longer carries that freight convincingly. The paradox of the Klitschko era is that their dominance has not inspired the rivalry to garland it. But there is serious money to be made and no little old-fashioned glory if the right champion comes along with a personality to match his talent in the ring.

Is Joshua that fighter? It is too early to say but he has the tools: size, power, skill, dedication – and a pleasing way about him.

His chosen route is understood to be through the promotional company of another great Olympic and world professional champion, Oscar De La Hoya. The deal is said to be for 10 fights. If Joshua decides to sign, he will be in good hands with the aptly named Golden Boy Promotions, who are also partners with Amir Khan and have access to the television heartbeat of American sport, HBO.

If all goes well, Joshua would return to the UK in two years' time a polished commodity, stepping back into a domestic scene that is bubbling up with promise. These are heady times for British boxing, promising times for the big men. But all that is some way in the future. Joshua's immediate task is to beat Cammarelle and grab that gold medal.

He has boxed better with each bout here, from the scarily nip-and-tuck effort against the young Cuban prodigy, Erislandy Savón, in the first round, through to his most mature performance, against the awkward Kazakh giant Ivan Dychko in Friday night's semi-final. He won by two points – according to the judges – but it was a clearer victory than that, as Joshua heeded the advice of Lennox Lewis (who also won Olympic gold and the world heavyweight title) to jab his way to a win.

Cammarelle, a better boxer than Dychko, had to work hard to beat Azerbeijan's reigning world champion, Magomedrasul Medzhidov, by a single point in the earlier semi-final, and that provides a relevant form line.

Joshua, after beating Cammarelle at the world championships in Baku, lost narrowly to Medzhidov in the final – in his home town, in front of his president. How did that affect the young British prospect? He admitted recently it might have been one of the best things to have happened to him.

"It wasn't a fight about the gold medal," he said. "It was a fight about pride. I look back, I'd love to have been world champion but at the time I put my hands up I thought I'd won. I said: 'Yes, I'm world champion.' And they gave it to him. When the bell went my body just shut down. Never been in pain like that before but I learnt so much.

"There's no turning back. Keep moving forward. I'm not bitter about it. I know how close it was. Being a world champion or an Olympic champion, it can be just one point. I don't want to leave it that close any more."

Joshua is right when he adds: "I'm a better fighter now. Not the best I can be. I'm not miles a better fighter than I was then but mentally it tested me as a person and what I'm about. If it gets tough, I'll stick in there."

There will be moments on Sunday afternoon when it will get very tough indeed. Cammarelle may never have made it as a pro but he has been a fine amateur champion, with a string of medals to show for it. Joshua has far fewer baubles but they are all bright ones and he is well capable of adding the one that matters most to his collection before he enters the shark-infested waters of the professional fight game.

"I don't worry about who's in the other corner," he said. "Most people in my weight are European champions, a junior Olympic champion, world medallists, Beijing champion, world champion, silver medallist, bronze medallist. Everyone around Europe, I know. And they're the tougher ones. There's no one that I'm worried about. If you want to be the best, you've got to beat the best."

Many fighters have said that. Many have said it at these Olympics. But after all the talk the numbers are reduced to two, then just one. Although it has come earlier than anyone expected, this looks like Joshua's time.